If we have to use a Load Balancer(LBR) to directly front-end the OAM Server instead of an intermittent OHS(probably due to cost constraints), we should have this LBR within the corporate network (in addition to an external LBR which front-ends the other OHS instance(s) for applications) and not in the DMZ to prevent the security risk of an external LBR based in the DMZ exposing the OAM located in the Application Tier directly.

Courtesy :
1) Forum Post which was logged as few items in the A-Team blog mentioned below were not crystal clear2) A-Team Blog